Induction heating head



May 7, w46. A H E. SOME@ 2,399,897

l INDUCTION HEATING HEAD Filedeb. 6, 1945 '2 shee-nsfsheet 1 owar'E Somes mvENvToR lBY May 7,1%6. H E. soMEs i lNDUCTON HEATING HEAD Filed Feb. e, 1945 2 sheets-sheet 2 fl@ I Howard, $077195 INVENTOR llllllll A1 @M ATTORNEY eccentric portions.

Patented'May 7, I

UNITEDv ls'rzrras PATENT oFFlca l 2,399,891

Howard 2131' to Budd Induction Bettini, Inn., lhildlphl corporation of Miohiltll Application February s, 194s, sensi Nc. 516,4; 1 s claims. (ci. zie-1a) This invention relates to induction heating heads, particularly to induction heating heads of the character utilized for electro-magnetically inducing high frequency .heating currents in the surface of an article to'be heat treated.

In the case of articles having oneor more circumferential grooves, such as for example, an arjticle having a ball bearing race which is desired to be hardened, it has been the practice to use a heating head having helical coil which was dis- 10 posed coaxially with respect to the article. In such .'cases,.it was not possible, due to the variable spacing -of the groove bottom from the coil, toheat the groove surface to a uniform depth,l This i gave undesirable, nony residual stresses which resulted from the heat 'treating operation. The object of the present invention is to provide an induction heating head of improved construction by means .of which the head and the 20 article to be heat treated can be disposed one within the other in such relation that circumferential grooves in the article can be heated to a uniform depth during relative rotation of the head and the article.

Another object is to provide an induction heating head with-a coil having eccentric projecting portions backed up by a magnetic core which ex- 'tends only for the circumferential extent of the With the above and other objects in view which will be apparent from the following vdetailed description to thosefskilled in the art to whichthe invention appertains, the present invention consists in certain features of construction and com'- 35` binations of parts to be hereinafter described with reference to the accompanying drawings, land then claimed.

1n the drawings which illustrate a' smtabie embodiment of the invention: t 40 Figure -1 is a vertical section taken through the Ainduction'heating head and showing the saine in operative relation with an internally grooved workpiece Figure 2 is a. transverse section taken approxi- 45 mately on line 2-,2 of Figure 1;

Figure 3 is a section taken approximately on line 3-3 of Figure i; and

Figure 4 is a 'side elevation of the heating head an insulating 11D8 n and bearing aainst the inshown in Figure 1. y, p Referring to' the accompanying drawings in which like numerals refer to like parts throulhiform distribution of the 15 an angle fitting I3.

55 about an outer conductor of the arbor.

The heating head is comprised of a'support I,

5 and within'this recess adjacent the lower end thereof, as viewed in Figure 1, with a semi-circular groove 5 which receives an arcuate element 3 having an angular upwardly'extending projection 1.

The core 2 is comprised of a plurality of tapered laminations of high magnetic permeability seated against theA bottom of the recess I and having notched portions 3 engaged or interlocked with the projection 1.

Associated with the upper end of the laminated core 2 is an arcuate element having a portion I4 fitting into notches in the upper end of the core laminations, and surrounding the support I is an annular shouldered ring I3 engaged with the element I3 and an upper end shouldered portion IB ofthe support -I. This ring is held in yclamping position against the element I3 and shoulder I6 by a nut I1 threaded onto the sup-- port I. j

A'Ihe upper end I3 of the coil 3 is provided with formed within the support I adjacent the lower end thereof as shown in broken outline in Figures 1 and 2.

The coil 3 is provided with a cooling fluid passage 22 which at the lower end communicates through an aperture 23 with an annular recess 24 formed in the lower end of the support I'.

The annular recess 23 is closed in by a suitable i closure plate 25. Extending upwardly, from the annular recess 2l a d through the upper end of the support I is a lzassage 26 having a tubular connector fitting 21 threaded thereinto.

The upper end of the support I is provided with of an arbor (not shown), the member 23 beingl carried by a clamping ring 33 which is clamped vCooling The laminated core 2 is formed Y with a side opening window 9, and the support ist The lower end 23 of the coil' 3 is inwardly turned to fit within Aan opening 2| fluid is introduced into the memb'er 23 and flows through the coil 3, thence through the annular passage 24 and is discharged through passageway G.

'I'he coil turns, at the portions opposite the core 2, are angularly offset as at 3i so that the turns, except for the offsets 3i, are parallel to each other and to a plane intersecting the axis of the coi.

In accordance with the present invention the coil turns are each provided with a transversely projecting portion 32 at the one side which are truly cylindrical for a portion of their extent and then gradually merge into the faces of the coil turns at about the terminations of the core 2. The diameter of the stantially the same as the diameter of the internal grooves 33 of the tubular article 34 to be heat treated. The cross sectional contour of the projections 32 corresponds substantially to the cross sectional contour of the grooves 33. It is to be understood, of course, that the projections 32 correspond in number and axial spacing to the grooves to be heated and that if only one'groove is to be heated, there will be only one such projection. The projections 32 may be an integral part of the coil turns or if desired they may be separate elements suitably secured to the outer faces of the coil turns. The maximum transverse dimension of the head through the projections is such that in practice the head can be disposed within the article 34. In practice, as set forth in my concurrently filed application Serial No. 576,410, the

head after being positioned within the article, is shifted so that its axis coincides with the axis of the projections 32 and to enter the projections within the grooves 33 while maintaining slight lclearance with the bottoms of the grooves. 'I'he head is then rapidly rotated about the axis of the projections with the result that upon energization of the coil the current flowing through the projections in cooperation with the semi-circular core 2 and during rotation of the head will induce heating currents in the surfaces of the grooves 33.

As a result of the semi-circular core 2, only those portions of the coil turns which are provided with the projections rents in the article.

By conforming the cross sectional contour of the projections substantially grooves, the groove surfaces are heated to a uniform depth with the result that after quenching, residual stresses resulting from the heat treating operation will be uniformly distributed.

It is to be understood that formal changes may be made in the detailed rangement of the parts described without deprojecting portions 32 is suby to that of the as oaeo? oneof the turns of said coil substantially for the extent of said core having a radially outwardly projecting portion, said one turn for the extent of said projecting portion being parallel to a piane transversely intersecting the axis of said coil.

2. An induction heating head comprising a cy-V lindrical support, a current conducting coil surrounding said support, and a magnetic core between said support and said coil for a portion only of the circumference ofsaid support, at least one of the turns of said coil substantially for the i extent of said core having a'radially outwardly projecting portion, said one turn for the extent of said projecting portion being parallel to a plane transversely intersecting the axis of saidv coil, said coil being insulated from said core and said support. y

3. An induction heating head comprising a cylindrical support having an arcuate recess in the peripheral surface thereof extending for a portion only of the circumferential extent thereof, an arcuate core seated in said recess, and a current conducting coil surrounding and being insulated from said core and coil, at least one of the turns of said coil being parallel to a plane transversely intersecting the axis of said coil, said one turn having a radially outwardly projecting portion extending circumferentially for substantially the circumferential extent of said core.

4. An induction heating head comprising a support, a current conducting |coil carried by said support, and an arcuate magnetic core adjacent the internal surface of said coil, said core extending for approximately one-half the periphery of vsaid coil, at least one of the turns of said coil for the extent of said core being parallel to a plane ,transversely intersecting the axis of said coil and for said extent having a portion extending radially outwardly from the outer surface thereof.

5. An induction heating head comprising a support, a current conducting coil carried by said 32 induce heating curconstruction and ar- Y parting from the .spirit and substance of the invention, the scope of which is defined by the appended claims.

What is claimed is:

1. An incfuction heating head comprising a cylindrical support, a current conducting coil sur' support, and an arcuate magnetic core adjacent the internal surface of said coil, said cere extending for approximately one-half the periphery of said coil, at least one of the turns of said coil for the extent of said core being parallel to a plane transversely intersecting the axis of said coil and for said extent having a portion extending radially-outwardly from the outer surface thereof, said outwardly extending portion having a 'cylindrical surface intermediate its ends and gradually merging at its ends into the surface of said turn.

6. An induction heating head comprising a cylindrical support having an arcuate recess in the external surface thereof, said recess extending for a portion only of the circumference of said support, a radially laminated magnetic core seatedin said recess, means locking said core in said recess, and a coil surrounding said support and core, at least one ofthe turns of said coil having an eccentric outwardly extending portion, said eccentric portion being substantially coextensive with said core.

HOWARD E. SOMES. 

